1. Field of the Invention
The present invention relates to an optical information recording medium (hereinafter referred to as an optical recording medium) of the heat mode type, and more specifically to an optical recording medium containing a specific compound as a quencher.
2. Description of the Prior Art
An optical recording medium of heat mode type utilizes recording light as the heat. An example of such a medium is a pit-forming type of medium where information is recorded by melting and removing parts of the medium with recording light such as a laser to form a pit, and the reading of a record is conducted by detecting this pit with reading light.
Various dyes or combinations of dyes with resins have been used in a recording layer of such optical recording media. However, such optical recording media have drawbacks such that the sensitivity or C/N ratio thereof is lowered by repeated erasing, repeated irradiation of reading light or long term preservation. Therefore, in order to improve light stability of the dye and to especially prevent decolorization owing to reading light (deterioration during reproduction), it has been proposed to use a dye and a quencher together (see, for example, Japanese Patent Published Unexamined Application (hereinafter referred to as J.P. KOKAI) Nos. 60-162691, 60-201988, 60-203488 and 60-257290).
However, even by combination with a quencher the durability of the optical recording medium against reading light, or the stability thereof during long term preservation has not yet been adequately satisfied from a practical point of view.